"I want more kids for sure, but I don't know when," says the 30-year-old model, mom to son Benjamin, almost 1, and stepson Jack, 3, with husband Tom Brady. "Right now I have my hands full!"

Adds Bundchen, "I'm feeling very lucky."

And for good reason: She says her boys rarely squabble.

"For Benjamin, his big brother is his hero," says the 5'11" stunner, who posed in lingerie less than five months after giving birth last year. "Jack comes in and Benjamin has a big smile. He wants to follow him around. Anything he does, he's just in awe of him like, 'Oh my God!'"

She admits Jack initially had a tough time adjusting to his little bro.

"Sometimes siblings can get in each other's space," she says. "He was used to having all the attention and then when you have to share, you don't like it."